NXP Semiconductors MMA6331LR1

Overview

MMA6331LR1 from Freescale Semiconductor is a surface-micromachined capacitive dual-axis (X/Y) accelerometer with integrated signal conditioning, selectable ±4g/±9g full-scale range, 1-pole switched-capacitor low-pass filter, and Sleep Mode. It delivers ratiometric analog outputs (XOUT/YOUT), operates from 2.2 V to 3.6 V, draws 400 µA active or 3 µA in Sleep Mode, and targets motion-sensing applications in battery-powered handheld electronics.

For engineers reviewing the MMA6331LR1 datasheet, MMA6331LR1 pinout, MMA6331LR1 application, or MMA6331LR1 equivalent, key selection criteria include g-select logic control, zero-g offset stability over temperature, output impedance matching for ADC interfacing, and PCB layout guidance for minimizing reflow-induced offset shift.

Technical Context

The MMA6331LR1 integrates a polysilicon MEMS g-cell sensor with an ASIC that performs capacitance-to-voltage conversion using switched-capacitor techniques. Its internal oscillator drives both sensing and filtering at 11 kHz, enabling a fixed 24 Hz typical bandwidth without external RC components.

Signal path includes temperature-compensated offset and sensitivity trimming stored in NVM, ratiometric output scaling with VDD, and digital control of gain via the g-Select pin (pin 10) and Sleep Mode (pin 7). Output stage features 32 kΩ internal series resistance and supports external 3.3 nF filtering per axis to suppress clock noise.

Key Specifications

Pinout & Package

Package: 14-lead LGA (3 mm × 5 mm × 1.0 mm, Case 1977-01), RoHS-compliant, surface-mountable with self-aligning footprint per Figure 8.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-axis analog accelerometer applications.

Compared with LIS302DL and ADXL322, the MMA6331LR1 uniquely combines factory-trimmed ratiometric analog outputs, integrated g-select logic, and ultra-low 3 µA Sleep Mode in a 3×5 mm LGA-making it optimal for cost-sensitive, battery-constrained motion UI and anti-theft systems requiring minimal external components.

Availability

MMA6331LR1 is available at Aetrix Electronics and suitable for smartphone motion UI, laptop anti-theft systems, pedometer activity tracking, and HDD MP3 player shock protection requiring stable component supply and long-term lifecycle support.

Supply support for MMA6331LR1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Freescale Semiconductor (now part of NXP Semiconductors) is a fabless semiconductor company specializing in embedded processing, sensors, and connectivity solutions for automotive, industrial, and consumer markets.

The MMA6331LR1 belongs to Freescale's Xtrinsic™ family of intelligent sensors, designed specifically for ultra-low-power motion sensing in portable consumer electronics where size, power, and ease of integration are critical.

FAQ

What is the recommended external capacitor value for filtering MMA6331LR1 analog outputs?

The MMA6331LR1 datasheet specifies a 3.3 nF capacitor on each analog output (XOUT and YOUT) to minimize clock noise from the internal switched-capacitor filter. This value yields a 1.5 kHz effective bandwidth, which exceeds the device's 24 Hz signal bandwidth and effectively suppresses 11 kHz sampling artifacts. Using a smaller capacitor increases noise susceptibility; larger values reduce bandwidth unnecessarily and may degrade transient response.

How does the g-Select pin affect sensitivity and full-scale range in MMA6331LR1?

The g-Select pin (pin 10) directly controls the MMA6331LR1's internal gain: a logic low selects ±4g range with 308 mV/g sensitivity, while a logic high selects ±9g range with 83.6 mV/g sensitivity. The pin has an internal pull-down, so leaving it unconnected defaults to ±4g mode. This hardware-selectable range allows one MMA6331LR1 design to serve multiple motion-detection use cases without firmware changes or external components.

What is the maximum mechanical shock the MMA6331LR1 can survive without damage?

The MMA6331LR1 is rated for ±5000 g mechanical shock across all axes, as specified in Table 1 of its datasheet. This rating applies to short-duration transient events (e.g., drop impacts onto concrete), not continuous acceleration. The robust polysilicon MEMS structure and hermetic wafer-level packaging enable reliable operation in handheld devices subjected to routine handling and accidental drops.

Does MMA6331LR1 require external calibration for zero-g offset or sensitivity?

No, the MMA6331LR1 does not require external calibration. Zero-g offset and sensitivity are factory-trimmed and stored in non-volatile memory (NVM), with temperature compensation applied internally. The device delivers calibrated analog outputs across its full operating temperature range (–40°C to +85°C) and supply voltage range (2.2 V to 3.6 V), eliminating the need for user calibration circuitry or software compensation algorithms.

What is the purpose of the separate VSS and GND pins on MMA6331LR1?

The MMA6331LR1 uses pin 5 (VSS) as the digital ground reference for internal logic and pin 13 (GND) as the analog ground reference for the MEMS sensor and output stage. Though both must connect to the system ground plane, separating them minimizes noise coupling from digital switching into the sensitive analog signal path. Layout best practices recommend connecting VSS and GND at a single point near the device and placing a solid ground plane beneath the entire LGA footprint.